Q.1
A new system of unit is evolved in which the values of µ0 and εo are 2 and 8 respectively. Then the speed of light in this system will be
  • a)0.25
  • b)0.5
  • c)0.75
  • d)1
Q.2
Our eyes respond to wavelength ranging from
  • a) 400nm to 700nm
  • b) 1mm to 700nm
  • c)-∞ to +∞
  • d)700nm to 800nm
Q.3
In microwave oven, we use electromagnetic oscillators which produce electromagneticwaves in the wavelength range
  • a) 1mm to 10m
  • b) 0.7µmto 1mm
  • c)0.1m to 1mm
  • d)0.1µmto 0.7µm
Q.4
A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% effecient in converting electrical power to electromagnetic waves and consumes 100W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 5m from the lamp will be
  • a) 1.34 V/m
  • b) 2.68 V/m
  • c)4.02 V/m
  • d)5.36 V/m
Q.5
The Sun radiates electromagentic energy at the rate of 3.9×1026 W. Its radius is 6.96×108 m . The intensity of sun light ( in W/m2) at the solar surface will be
  • a) 5.6×106
  • b) 5.6×107
  • c) 4.2×106
  • d) 4.2×107
Q.6
An electromagnetic wave of frequency ν=3.0 Mhz passes from vacuum into a dielectric medium with permitivity ε=4.Then [ AIEEE 2004]
  • a)Wavelength is doubled and frequency remains unchaged
  • b) Wvaelength is doubled and frequency becopmes half
  • c)wavelength is doubled and frequency becomes half
  • d)wave length and frequency both remains unchaged
Q.7
The electrical conductive it of earth's atmosphere increases with altitude because of [ Bihar CECE 2004]
  • a) reflection of atmospheres
  • b) accelerated protons
  • c)measure of voltagae
  • d)measure of charge
Q.8
If the wavelength of light is 4000 Å then the number of waves in 1mm length will be [ JKCET 2004]
  • a) 25
  • b) 0.25
  • c)0.25×104
  • d)2.5×104
Q.9
Sodium lamps are used in foggy conditions because
  • a) yellow light is scatered less by the fog particles
  • b) yellow light is scattered more by the fog particles
  • c) yellow light is unaffected during its passage through the fog
  • d) wavelength of yellow light is the mean of visible part of the sprectrum
Q.10
The rms value of electric field of the radiation coming from sun is 720 N/C, The average radiation density in J/m3 is ..
  • a)81.35 × 10-12
  • b) 3.3 × 10-3
  • c)4.58 × 10-6
  • d)6.37 × 10-9
Q.11
In the region closer to the oscillating charges, the phase difference between E and B fields is ... and their magnitude quickly decreases as ... with distance r from the source
  • a) 0, r-1
  • b) π/2, r-3
  • c)π/2, r-1
  • d)0, r-3
Q.12
At room temperature, if the relative permittivity of water be 80 and the relative permeability be 0.0222, then the velocity of light in water is ... m/s
  • a)3×108
  • b) 2.5×108
  • c)2.25×108
  • d)3.5 ×108
Q.13
If the electric field asssociated with a radiation of frequency 10 MHz is E=10sin( kx -ωt) mV/m . then its energy density in J/m3 is [ εo=8.85×10-12C2N-1m-2]
  • a) 4.425×10-16
  • b) 6.26×10-14
  • c) 8.85×10-16
  • d) 8.85×10-14
Q.14
In hertz's experiment the .... of the electromagnetic waves is equal to the kinetic energy of the charges oscillating between the two spheres
  • a)frequency
  • b) energy
  • c)wavelength
  • d)velocity
Q.15
The etensity of plane electromagnetic wave with Bo=1.0×10-4T in W/m2 is ..
  • a) 2.38×106
  • b) 1.19×106
  • c)6×105
  • d)4.76×106
Q.16
The magnetic field of an electromagnetic plane travelling along the negative X-direction is given by By=2×10-7 sin(0.5×103 x + 1.5×1011 t ) T what is the wavelength and frequecy of the wave
  • a) 1.26 m, 23.9 Hz
  • b) 2.56 cm, 12.0 GHz
  • c)3.21 m , 36.2 GHz
  • d)1.26 cm, 23.9 GHz
Q.17
For a radiation of 6 GHz passing through air, the wave number ( number of waves) per 1 m length is ...(1 GhZ=109 Hz)
  • a) 3
  • b) 5
  • c) 20
  • d) 30
Q.18
The power in a two-wire transmission line travels
  • a)inside the conductors
  • b) outside the conductors
  • c)none of the above
  • d)both inside and outside the conductors
Q.19
The characteristic impedance of a lossless transmission line is given by
  • a) Zo=√LC
  • b) Zo=√ (L/C)
  • c)Zo=√(C/L)
  • d)Zo=LC
Q.20
An 'antenna' is
  • a) inductive
  • b) capacittative
  • c)resistive above its resonance frequency
  • d)none of the above
Q.21
A laser is a coherent source because it contains
  • a) many wavelengths
  • b) uncoordinated wave of a particular wavelength
  • c) coordinated wave of many wavelengths
  • d) coordinated waves of a particular wavelength
Q.22
A modulating signal of frequency 5kHz and peak voltage of 6V is used to modulate a carrier of frequency 10 MHz and peak votage of 10V. what is modulation index
  • a)1.66
  • b) 0.6
  • c)2
  • d)0.5
Q.23
In above problem (Q161) what is Low side band frequency (LSB)
  • a) 10.005 MHz
  • b) 0.05 MHz
  • c)22 MHz
  • d)9.995 Mhz
Q.24
In problem Q161 What is upper side band frequency (USB)
  • a)10.005 MHz
  • b)0.05 MHz
  • c)22 MHz
  • d)9.995 MHz
Q.25
In problem Q161 what is the amplitude of LSB and USB
  • a) 3V, 6V
  • b) 6V, 3V
  • c) 3V , 3V
  • d) 6V, 6V
Q.26
Who produced the electromagnetic waves first ?
  • a)Marconi
  • b)Maxwell
  • c)J.C. Bose
  • d)Hertz
Q.27
A plane electromagnetic wave is incident on a material surface. The wave delivers momentum P and energy E
  • a) P=0, E ≠ 0
  • b)P ≠ 0, E=0
  • c)P ≠ 0, E ≠ 0
  • d) P=0, E=0
Q.28
If Vγ Vx and Vm are the velocity of the γ rays, x rays, micro waves respectively inspace, then
  • a)Vγ < Vx < Vm
  • b) Vγ=Vx=Vm
  • c)Vγ > Vx > Vm
  • d)Vγ > Vx < Vm
Q.29
If λγ ,λx and λm are the wave lengths of the γ rays, x rays and micro waves respectivelyin space then
  • a) λγ > λx > λm
  • b) λγ < λx < λm
  • c) λγ=λx=λm
  • d) λγ >λm > λx
Q.30
According to Maxwell, a changing electric field produces
  • a)emf
  • b) Electric current
  • c)magnetic field
  • d)radiation pressure
0 h : 0 m : 1 s